Relay counting circuit

ABSTRACT

A relay circuit responsive to input impulses, represented by the closings and openings of a push button switch, wherein the relay circuit includes at least two relay windings and contacts and conductors interconnected to permit each closing and each opening of the push button switch to bring about a change in the energization state of the relays in the circuit. The basic circuit includes two windings in series circuit relationship with a contact set operated by one of the windings, the other winding being coupled to operate two single-pole double-throw contact sets capable of connecting one of two shunt circuits across one of the windings and the normally open contact set. Four events (two closings and two openings) of the push button switch cause the circuit to take four distinct and identifiable states. Outputs from the winding can be used to feed an appropriate logic circuit and display means, if desired. More sophisticated versions using transistor relay drive and embodiment using sets of four and six relay windings, with appropriate steering diodes and the like, are disclosed. In each case each relay contact set opens and closes under conditions of zero potential difference, thereby eliminating arcing and greatly extending contact life.

United States Patent Gruenwald [54] RELAY COUNTING CIRCUIT [72] lnventor: Bjorn J. Gruenwald, Easton, Pa. [73] Assignee: Alpha Press Electronics, Inc., Alpha,

22] Filed: Sept. 17,1971

211 Appl.No.: 181,461

[52] us. or "317/140 [51] int. c1. ..H01h 47/00 581 Field of Search ..317/140 [56] References Cited UNITED STATES PATENTS 3,129,362 4/1964 Gilbert ..317/140 Primary Examiner-L. T. Hix Attorney-D. C. Roylance et al.

[ ABSTRACT A relay circuit responsive to input impulses,

- Oct. 24, 1972.

represented by the closings and openings of a push interconnected to permit each closing and each opening of the push button switch to bring about a change in the energization state of the relays in the circuit. The basic circuit includes two windings in series circuit relationship with a contact set operated by one of the windings, the other winding being coupled to operate two single-pole double-throw contact sets capable of connecting one of two shunt circuits across one of the windings and the normally open contact set. Four events (two closings and two openings) of the push button switch cause the circuit to take four distinct and identifiable states. Outputs from the winding can be used to feed an appropriate logic circuit and display means, if desired. More sophisticated versions using transistor relay drive and embodiment using sets of four and six relay windings, with appropriate steering diodes and the like, are disclosed. In each case each relay contact set opens and closes under conditions of zero potential difference, thereby eliminating arcing and greatly extending contact life.

5 Claims, 8 Drawing Figures PATENTED B 19?? 3. 700.973 sum 1 nr 4 BJORN GRUENWALD BY 55/ M 73% ATTORNEYS.

PAIENTEDucI 24 I972 SHEEI 2 BF 4 INVENTOR BJORN GRUENWALD BY F 2/24 ATTORN E Y5,

PATENTEDUBI 24 m2 SHEEI 3 OF 4 ATTORNEYS.

PMENTEBIJBI 24 I972 SHEEI '4 0F 4 INVENTOR BJORN GRUENWALD ATTORNEYS.

1 RELAY COUNTING CIRCUIT This invention relates to counting circuits and, more specifically, to counting circuits including electromagnetic relays.

Various forms of relay circuits have been developed over the many years during which electromagnetic relays have been known and used, and over the many years that pulse counting has been of value. In more recent years, semi-conductor devices have nearly preempted the counter field, almost to the exclusion of electromagnetic relays.

A major advantage of solid state semi-conductor circuits having few or no moving parts is, quite simply, that there are very few parts to fail so that the circuit life is greatly extended and the. circuit reliability is extremely high. However, thereare some disadvantages to solid state circuits, including susceptibility under some conditions to electrical and magnetic fields of the magnitude which can be present on large industrial machines.

Electromagnetic relay circuits, which are not generally susceptible to the kinds of fields which can affect semi-conductor circuits, or which can be rendered unaffected by them, have other diadvantages, one or more of which have led to the trend toward semi-conductor circuits. One of the major disadvantages is that relay circuits necessarily involve contacts which, when they come together and separate, undergo a phenomenon known as arcing and are thereby affected by pitting, burning and other effects which drastically diminish the life of the contacts and, therefore, the life of the relay.

Other disadvantages of electromagnetic relays, including size and sensitivity, have largely been avoided simply by advances in the art of relay design. Thus, a

glass enclosed reed switch, which may have mercury wetted contacts, is a very small, highly sensitive and highly reliable device which approaches solid state circuits in utility, but is nevertheless, subject to arcing and contact destruction.

A- principal object of the present invention is to provide various embodiments of. electromagnetic relay counting circuits in which all relay contacts are opened and closed under conditions of zero current or potential difference, thereby eliminating degradation of the contacts due to arcing.

Another object of the present invention is to provide a plurality of counting circuits capable of assuming a variety of energization states representative of a number of units to be counted.

Briefly described, the present invention includes a first electrically conductive path connected across a power supply, the path including a series circuit having a first and second electromagnetic operators and a first switch actuated by energization of one of the electromagnetic operators, and second and third electrically conductive paths, each of which is connectable across one combination of an electromagnetic operator and the first switch. The second and third paths have a common portion which includes switch means operative in response to the eventst'o be counted. A third switch means is actuated by the other electromagnetic operator and is effected to connect one of the second and third paths across its respective associated circuit.

. In order that the manner in which the foregoing and other objects are attained in accordance with the invention can be understood in detail, particularly advantageous embodiments thereof will be described with reference to the accompanying drawings, which form. a part of this specification and wherein:

FIG. 1 is a'schematic diagram of a basic counting circuit in accordance with the invention;

FIG. 2 is a schematic diagram of a two-relay counting circuit using transistors in accordance with the present invention;

FIG. 3 is a schematic diagram of a four-relay counting circuit in accordance with the invention;

FIG. 4 is a schematic diagram of an alternative version of the two-relay circuit of FIG. 1;

FIGS. 5 and 6 are alternative arrangements of four relay counting circuits, FIG. 6 employing'transistors;

FIG. 7 is an alternative arrangement of a four-relay counting circuit using four transistors; and

FIG. 8 is a schematic diagram of a six-relay counting circuit in accordance with the invention.

In the basic circuit of FIG. 1, the existence of 'and connection to a power supply is indicated by two power lines 10 and 11, conductor 10 being the positive side and 11 being the negative'side of the power supply. One terminal of the energizing winding 12 of an electromagnetic relay is connected to conductor 10, the other terminal of the relay winding being connected to one terminal of a normally open contact set indicated generally at 13, contact set 13 being closed by energization of winding 12. The other terminal of contact set 13 is connected to'one terminal of the energizing winding 14 of an electromagnetic relay, the other terminal of that winding being connected to conductor 1 l.

Winding 14, when energized, operates two contact sets indicated generally at 15 and 16, each being a single pole double-throw contact set. The normally open fixed contact of contact set 15 is connected by a conductor 17 to positive conductor 10, and its normally closed fixed contact connected by a conductor 18, to the junction between winding 12 and contact set 13. Similarly, the normally closed fixed contact of contact set 16 is connected by a conductor 19 to negative conductor 11, and the normally open contact of that set is connected to the junction between contact set 13 and winding 14 by a conductor 20. The movable contact of each of contact sets 15 and 16 is connected to one terminal of a switch indicated generally at 21. Switch 21 is shown, and will be discussed, as a normally open push button switch-It can be regarded as a bi-stable, twoposition device capable of completing a circuit in one position and incapable of doing so in the other position. The actual structure of the device, whether it be mechanically operated, manually operated, electronically actuated, or otherwise is of no special consequence. However, the existence of the switch and its operation are of considerable importance to the invention because it is the closings and openings of that switch which will be counted by the circuit of FIG. 1, and of analogous switches in each of the other embodiments to be discussed hereafter.

To understand the operation of the circuit of FIG. 1, it will be assumed at the outset that all switches are v shown in their normal or deenergized conditions and 3 circumstance, the circuit can be said 'to be in a state in which winding 12 is deenergized and winding 14 is also deenergized. This will be defined as a zero state.

Then, assume that switch 21 is closed. A conductive path including winding 12, contact set 15, switch 21, contact set 16 and conductor 19 is completed, permitting winding 12 to be energized and closing contact set 13. As soon as contact set 13 is closed, there is a circuit through that contact set and winding 14. However, relay winding 14 would not be expected to energize because it is by-passed by the low resistance shunt circuit including conductors 18 and 19, contact sets and 16, and switch 21. The circuit is then in its first non zero state with winding 12 energized and winding 14 deenergized. I

The next change occurs when switch 21 opens. This removes the shunt .circuit around winding 14, permitting winding 14 to energize and causing contact sets 15 and 16 to move to the positions opposite from that shown in FIG. 1. The circuit is then in its second state with windings 12 and 14 both energized and contact sets 13, 15 and 16 all in their closed or energized positions.

A second closure of switch 21 provides a shunt circuitaround winding 12, this circuit including conductors l7 and 20, contact sets 15 and 16 and switch 21.

Winding 12 is therefore caused to deenergize, permitting contact set 13 to open. The circuit is then in its third state with winding 12 deenergized and winding 14 energized.

The next opening of switch 21 removes the shunt cir- I cuit around-winding 12 which had been maintaining winding 14 in its energized condition, thus permitting Winding 14 to deenergize and permitting contact sets 15 and 16 to return to the positions shown in FIG. 1. The circuit is then returned to its fourth state, which is identical with the zero state initially assumed.

Some observations can now be made about the circuit, its operation and its characteristics. First, it will be seen that the circuit is capable of assuming four distinct and identifiable states, each of which can easily be detected simply by placing voltage sensors or current sensors in appropriate places in the circuit and connecting these to logic elements. Such a variety of sensing operations are possible that it seems pointless to unnecessarily complicate this basic circuit with some devices and they have therefore been omitted. The fact remains that the four states can exist and can be detected and utilized.

I A second observation is that each of the contact closings and openings of contact sets 13, 15 and 16 are accomplished under conditions of zero potential difference, thereby eliminating any tendency for the closing or opening contacts to arc and, as a result, extending the life of the contacts tremendously. For example, it will be seen that when switch 21 is first closed winding 12 is energized and contact set 13 is closed. However, at that time, there is no potential difference across contact set- 13. Thus, there is no tendency for an are I to be produced as the contacts close. Similarly, when switch 21 opens and relay winding 14 is energized by the removal ofthe shunt circuit, contact sets 15 and 16 are moved to their energized positions, but, at that time there is a zero, or substantially zero, potential difference across the contacts, thereby eliminating any a 4 tendency to arc. It be observed that although there is a potential .difierence between the open and closed fixed contacts of either contact set, there is essentially no potential difference between the normally open and movable contacts, therebyeliminating the tendency to are.

ltwill be seen that the-circuit of FIG. 2 is somewhat similar to that of FIG. 1, but incorporates transistors to facilitate relay switching. However, the basic principle employed in the embodiment of FIG. 1 is still present,

i.e., there is a basic circuit including the two relay windings and a contact operative in response to the energization of one of the windings, and thensecond and third circuits having a portion in common which can be selectively placed in parallel circuit relationship with one of the windings and the contact set, the second and third portions being selected by energization of the other winding, the common portion having a switch operated by external means, and closings and openings of the switch being counted by changes of the state in the circuit.

In accordance with this principle, FIG. 2 includes a relay winding 22, a contact set 23 which is normally open and which is closed by energization of winding of 22, and a relay winding 24, the two windings and the contact set being connected in series circuit relationship between conductors 10 and 11. A conventional NPN transistor indicated generally at 25 has a collector electrode connected to the conductor between winding 22 and contact set 23, a base electrode connected to conductor 10 and'an emitter electrode connected to the anode of a conventional semi-conductor diode 26. A conventional PNP transistor indicated generally at 27 has a collector electrode connected to conductor 11, a base electrode connected to the junction between contact set 23 and winding 24, and an emitter electrode connected to the cathode of a conventional semi-conductor diode 28.

Two single-pole, single-throw contact sets indicated generally at 29 and 30 are actuated by the energization of relay winding 24, these contact sets being connected to the terminals of a manually operated normally open switch indicated generally at 31. Contact set 29 is connected between conductor 10 and the junction of the cathode of diode 26 and one terminal of switch 31; while contact set 30 is connected between the junction of contact set 23, winding 24and the base electrode of transistor 27, and the junction of switch 31 and the anode of diode 28. r

' In operation, the circuit of FIG. 2 can be assumed to initially exist in the deenergized state as shown. The first event to be counted is the first closing of switch 31 which completes a current path through relay winding 22, the emitter-collector circuit of transistor 25, diode 26, switch 31, diode 28, the emitter-collector circuit of transistor 27 and conductor 11. This permits relay 22 to be energized and causes contact set 23 to close.

- cuit shunts relay winding 22 and permits that which completes a circuit through contact set 29,

switch 31, switch 30 and relay winding 24, which cirwinding to deenergize, opening contact set 23. Finally, switch 31 is opened, breaking the circuit which had held relay winding 24 in its energized condition, thereby permitting that winding to be deenergized and permitting contact sets 29 and 30 to again open.

An examination of each step will demonstrate that, as described with reference to FIG. 1, four states of the circuit exist, which states can easily be detected and utilized, by suitable logic circuitry. Furthermore, it will be observed that each opening and closing of a contact set is accomplished under conditions which do not per- .mit any arcing to. occur across those contact sets, thereby completely eliminating a majorcause of relay failure.

It will be recognized at this stage, by those skilled in the art, that multiple circuits like that shown in FIG. 2 can be utilized in decade fashion, thereby permitting events to be counted in a number system of base four. However, it will also be recognized that this has some. drawbacks, and that a single circuit capable of counting more events would be more desirable. Such a circuit will now be described.

FIG. 3

In the circuit of FIG. 3 there is, again, the basic series curicuits of a relay winding 32, a normally open singlepole contact set 33 which is operated by winding 32, and a second relay winding 34, these elements being connected between power supply conductors l0 and A second series circuit including a relay winding 36, a relay winding 38 and a normally open contact set 37 operated by relay winding 38, are connected in series between conductors l0 and 11. It will be observed that the four relay windings and associated circuitry are connected to count the closings and openings of a manually operated switch indicated generally at 41.

Winding 3.4 is connected to actuate two single-pole double-throw contact sets indicated generally at 39 and 40, the movable contact of each of these contact sets being connected to the terminals of switch 41. The normally open fixed contact of set 39 is connected to conductor 10 and the normally closed fixed contact of contact set 40 is connected to conductor 11. The remaining fixed contacts of sets 39 and 40 are connected to the movable contacts of single-pole double-throw contact sets 42 and 43 which are mechanically coupled to be operated by relay winding 36. The normally open contact of contact set 42 is connected to the cathode of a conventional semi-conductor diode 44, the anode of which is connected to the junction between winding 36 and contact 37, the normally open contact also being connected to the cathode of a diode 45. The normally closed fixed contact of set 42 is connected to the cathode electrodes of diodes 46 and 47, the anode of diode 47 being connected to the junction between winding 32 and contact set 33. The normally closed fixed contact of set 43 is connected to the anodes of diodes 48 and 51, the cathode of diode 48 being connected to the junction between winding 38 and contact set 37. The normally open fixed contact of set 43 is connected to the anodes of diodes 49 and 50, the cathode of diode 50 being connected to the junction between winding 34 and contact set 33.

It will be observed that the anodes of diodes and 46, and the cathodes of diodes 49 and 51, are connected to terminal labeled D, A, C, and B, respectively. These are output signal terminals which will be discussed hereinafter but which can be ignored for the moment.

The operation of the circuit of FIG. 3 is fundamentally the same as the circuits of FIGS. 1 and 2, but, oh-

' viously, involves a longer sequence of steps. First, as-

surning that the circuit is initially in the deenergized situation as shown, the first event is the closure of switch 41 which completes a circuit through winding 32, diode 47, contact set 42, contact set 39, switch 41 and contact set 40 to conductor 11. This energizes winding 32 and closes contact set 33. As before, the circuit through switch 41 is a shunt for winding 34 so that that relay does not energize.

The next event is the opening of switch 41 which removes the shunt and permits winding 34 to be energized. This causes contact sets 39 and 40 to move to the positions opposite those shown in FIG. 3.

The next event is the second closing of switch 41 which completes a circuit from conductor 10 through contact set 39, switch 41, contact set 40, contact set 43,and diode 48 through winding 38 to conductor 11, permitting energization of winding 38 and closing of contact set 37. The circuit thus described is a shunt for winding 36 so that the winding is not energized.

Opening of switch 41 removes the shunt circuit and permits winding 36 to be energized, causing contact sets 42 and 43 to move to the positions opposite those shown in FIG. 3.

At this stage, four events have occurred and the circuit of FIG. 3 can be characterized as fully energized,

-i.e., all of relay windings 32, 34, 36 and 38 are energized and all of the contact sets are in the condition opposite those shown in FIG. 3.

The next event is the third closing of switch 41 which completes a circuit from conductor 10 through contact set 39, switch 41, switch 40, switch 43, diode 50 and winding 34 to conductor 11. This circuit shunts winding 32, causing it to be deenergized and opening contact set 33. Relay winding 34 is maintained in its energized condition by the shunt circuit.

The next event is the opening of switch 41 which removes the shuntcircuit and causes winding 34 to be deenergized returning contact sets 39 and 40 to the position shown in FIG. 3.

The next event is the fourth closing of switch 41 which completes a circuit from conductor 10 through winding 36, diode 44, contact set 42, contact set 39, switch 41 and contact set 40 to conductor 1 1. This provides a shunt circuit for relay winding 38, permitting that winding to deenergize and opening contact set 37. Winding 36 is maintained in the energized condition by the shunt circuit.

The final event is the opening of switch 41 which breaks the shunt circuit, causing the winding 36 to be cuit to the original condition shown in FIG. 3, eight events having been counted.

Again, it will be. observed that all of the openings and closings of the various relay contact sets are accom-' plished under zero voltage and current conditions so that no arcing takes place.

The matter of utilizing outputs can be discussed with reference to FIG. 3. It will be seen that detecting the states of energization of the various relay windings can be used as a logic output from the counting circuit to decoding means of any desired variety (e.g., a matrix) to provide a useable output display. The states of energization of the windings can be detected, for example, by simply combining an extra set of contacts with each relay. Other techniques are also available and will be easily recognized.

Following is a table showing the various energization states of therelay windings in the sequence of events discussed above.

TABLE I EVENT WINDING 32 34 36 38 Zero state 0 0 0 lst closing I 0 0 O lst opening I I 0 0 2nd closing I l 0 l 2nd opening I I I 1 3rd closing 0 l l I 3rd opening 0 0 I I 4th closing 0 O I 0 4th opening 0 0 0 (I energized In addition to the above, other outputs can be detected, a typical output being shown in FIG. 3 by the diodes 45, 46, 49 and 51, and the output terminals labeled A, B, C and D. The following is a table showing the state at those terminals, terminals A and D being measureable with respect to conductor and terminals B and C being measured with respect to conduc- For purposes of completeness, the circuit of FIG. 4 is included, although it represents merely a variation in the manner of connection of the circuit of FIG. 1. Nevertheless, the specific arrangement of conductors and switches may be a useful alternative.

.8 i In the circuit of FIG. 4 relay windings 55 and 56 are connected in series circuit relationship with a normally open contact set indicated generally at 57, thecontact set being actuated by winding 55. Winding 56 is mechanically coupled to operate two single-pole double-throw contact sets indicated generally at 58 and 59, the movable contacts ofthese contact sets being connected'to the terminals of a push button switch indicated generally at 61. The-fixed contacts of contact set 58 are connected to opposite sides of contact set 57 so that movement of the movable contact of set 58 connects the push button to one side or the other of that contact set.'The fixed contacts of contact set 59 are connected to positive and negative conductors 10 and 11, respectively, with the contacts arranged so that when one switch is connected toward the positive conductor the other is connected toward the negative conductor and vice versa.

The operation of the circuit of FIG. 4 is essentially the same as that of FIG; 1, the first closing causing energization of winding 55, the first opening causing energization of winding 56, the second closing causing deenergization of winding 55 and the second opening (the fourth event) causing deenergization of winding 56. No further description of this circuit is deemed necessary.

FIG. 5

The circuit of FIG. 5 is an alternative arrangement for a four-relay system but with difierent switchin connections and contact arrangements, which circuit may be useful in some circumstances. In the circuit of FIG. 5 relay windings 62 and 63 are connected in series circuit relationship with a normally open contact set indicated generally at 64 between conductors l0 and 11, contact set 64 being operated by winding 62. Two single-pole double-throw contact sets indicated generally at 65 and 66 are actuated by energization of winding 63, the normally closed fixed contact of contact set 65 beingconnected to the junction between winding 62 and contact set 64, and the normally open fixed contact of contact set 66 being connected to the junction between contact set 64 and winding 63.

A second series circuitconnected between conductors 10 and 11 includes relay windings 67 and 68 which are connected in series circuit relationship with a normally open contact set 69 which is operated by winding 67. The normally open fixed contact of contact set 65 is connected to the junction between winding 67 and contact set 69 and the normally closed fixed contact of contact set 66 is connected to the junction between winding 68 and contact set 69.

Winding 68 is mechanically coupled to operate two single-pole double-throw contact sets indicated generally at 72 and 73, the movable contact of these contact sets being connected to the two terminals of a push-button switch indicated generally at '71. The movable contacts of contact sets 65 and 66 are connected to the normally closed and normally open fixed contacts, respectively, of contact set 72. The normally closed fixed contact of contact set 73 is connected to negative conductor 11 and the normally open contact of that set is connected to positive conductor 10.

In the operation of the circuit of FIG. 5, closing switch'7l completes a circuit from conductor 10 including winding 62, contact sets 65 and 72, switch 71 and contact set 73 to conductor 11. Winding 62 is thereby energized, closing contact set 64. The subsequent opening of switch 71 removes the shunt circuit around winding 63, permitting that winding to be energized and causing contact sets 65 and 66 to change position. The next closing of switch 71 provides a circuit from conductor 10 through winding 67, contact set 65, contact set 72, switch 71 and contact set 73 to conductor 11, energizing relay 67 and closing contact set 69. The next opening of switch 71 permits winding 68 to be energized through winding 67 and contact set 69.

At this stage, all relays are energized and all contact sets are in the positions opposite those shown in FIG. 5.

The next closure of switch 71 completes a circuit from conductor 10 through contact set 73, switch 71, contact sets 72 and 66 and winding 63 to conductor 1 1, shunting winding 62 and permitting that winding to be deenergized, opening contact set 64; The next opening of switch 71 permits winding 63. to be deenergized. The next closing of switch 71 completes a circuit from conductor 10 through contact set 73, switch 71, contact set 72, contact set 66 and winding 68, by passing winding 67 and permitting that winding to deenergize with the resultant opening of contact set 69. The next opening of switch 71 deenergizes winding 68, returning the circuit to the condition shown in FIG. in which it is fully deenergized.

Again, all contact openings and closings are accomplished without potential difference across the contacts, thereby eliminating arcing.

FIG. 6

The circuit of FIG. 6 utilizes four relay winding and employs transistors to. improve and facilitate switching. The circuit includes relay windings 75 and 76 which are connnected in series circuit relationship with a normally open contact set indicated generally at 77 between positive and negative conductors and 11. Contact set 77 is actuated by the energization of winding 75, while winding 76 is mechanically connected to operate a normally open contact set .indicated generally at 78 and a normally closed contact set indicated generally at 79. Contact sets 78 and 79 are connected in series circuit relationship with a push button switch indicated generally at 81 between conductors 10 and 11. A third series circuit including relay windings 82 and 83 and a normally open contact set indicated generally at 84 is connected between conductors 10 and 11. contact set 84 is operated by energization of winding 83. Winding 82 is mechanically coupled to operate two normally open contact sets indicated generally at 85 and 86. Contact set 85 is connected in series circuit relationship with a conventional semiconductor diode 87, this series circuit being connected at one end to the junction between contact set 78 and switch 81, and at the other end to the junction between winding 82 and contact set 84. The emitter electrode of an NPN transistor indicated generally at 88 is connected to the junction between diode 87 and contact set 85. The collector electrode of the transistor is connected to the junction between winding 75 and contact set 77, and the base electrode is connected through a resistor 89 to the junction between winding 82 and contact set 84.

A conventional semi-conductor diode 90 is connected in series circuit relationship with the emittercollector circuit of a PNP transistor indicated generally at 91, the diode end of the series circuit being connected to the junction between switch 81 and contact set 79, and the collector electrode being connected to the junction between winding 83 and contact set 84. The base electrode of the transistor is connected through a resistor 92 to the junction between contact set 77 and winding 76 and also to one side of contact set 86, the other side of that contact set being connected to the emitter electrode of transistor 91.

The operation of the circuit of FIG. 6 is quite similar to the operation of the versions without transistors, the difference being the more expeditious action of the relay resulting from transistor amplifier action. Commencing with the circuit in the state shown in FIG. 6,

the first event to be counted is the first closing of switch 81 which completes a circuit through relay winding the collector-emitter circuit of transistor 88, diode 87 switch 81 and the normally closed contact set 79 to conductor 11. The base of transistor 88 being connected to essentially the full positive potential of conductor 10 through winding 82, transistor 88 is conductive and winding 75 is energized, closing contact set 77. Opening switch 81 removes the shunt circuit bypassing winding 76, permitting that winding to be energized, thereby closing contact set 78 and opening contact set 79. The next closing of switch 81 completes a circuit from conductor 10 through contact set 78, switch 81, diode 90, the emitter-collector circuit of transistor 91 and winding 83 to conductor 11, thereby energizing winding 83 and permitting contact set 84 to close. The next opening of switch 81 removes the shunt circuit bypassing winding 82, permitting that relay to be energized and closing contact sets and 86.

The next four closings and openings of switch 81 sequentially deenergize the relays in a manner similar to that previously described. Again, it will be observed that the contact openings and closings take place under no current conditions.

FIG. 7

The circuit of FIG. 7 is a still further development along the lines of FIG. 6 but wherein four transistors are used rather than two, the advantage again being quicker and more definite relay action. However, the circuit is still basically a four-relay circuit and involves a truth table similar to Table 1 above.

In the circuit of FIG. 7 relay windings 95 and 96 are connected in series circuit relationship with a normally open contact set 97, contact set 97 being operable by energization of relay 95. Winding 96 is connected to operate normally open contact sets 98 and 99. Contact set 98 is connected in series circuit relationship with a push-button switch 101. and with a conventional semiconductor diode 102 and the emitter-collector circuit of a conventional PNP transistor indicated generally at 103, between conductors 10 and 11. One side of contact set 99 is connected to the junction between switch 101 and diode 102, and the other side of switch 99 is connected through a resistor 104 to the base electrode of transistor 103. The emitter electrode of a conventional PNP transistor indicated generally at 105 is connected through a diode 106 to contact set 99, and also,

through a resistor 109, to the base electrode of transistor 105.

The collector electrode of transistor 105 is connected to the junction between a relay winding 110 and,

a normally open contact set 1 11, which is operated by energization of winding 1 10, the relay winding and contact set being connected in series circuit relationship between conductors and 11 with a relay winding 112. Winding 112 is mechanically coupled to operate normally open contact set 108 and also normallyopen contact set 1 13, the latter being connected in series circuit relationship between the junction of winding 112 and contact set 111 and the junction between switch 101 and contact set 98 with the emitter-collector circuit of a conventional NPN transistor indicated generally at 114 and a conventional semi-conductor diode 115. The base of transistor 114 is connected through a resistor 1 16 to conductor 10.

One side of switch 114 is connected through a resistor 117 to the base electrode of a conventional NPN transistor indicated generally at 1 18, the collector electrode of which is connected to the junction between winding 95 and contact set 97 and the emitter electrode of which is connected through a diode 119 to the other side of switch 113 and the collector electrode of transistor 114.

In operation, closing switch 101 completes a circuit from conductor 10 through winding 95 through the collector-emitter circuit of transistor 118, diode 119, the collector-emitter circuit of transistor 114, diode 115, switch 101, diode 102 and the emitter-collector circuit of transistor 103 to conductor 11. The base electrodes of transistors 114 and 118 are connected, indirectly, to the positive conductor and the base electrode of PNP transistor 103 is connected indirectly to the negative line, rendering these three transistors conductive and permitting energization of winding 95, thereby closing contact set 97. Opening switch 101 breaks the shunt circuit bypassing winding 96, permitting energization of that winding and the closing of contact sets 98 and 99. The next closing of switch 101 completes an additional circuit through contact set 98, switch 101, contact set 99, diode 106, the emitter-collector circuit of transistor 105 and winding 1 10, energizing that winding and closing contact set 11 1. The next opening of switch 101- permits energization of winding 112, closing contact sets 108 and 113. The next closing of switch 101 completes a circuit through contact set 98, switch 101, contact set 99, contact set 108 and relay winding 96, bypassing winding 95 and permitting the deenergization of that winding with opening of contact set 97 The next opening of switch 101 permits deenergization of winding 96 with the opening of contact sets 98 and 99. The next closing of switch 101 completes a circuit through winding 112, contact set 113, the collectoremitter circuit of transistor 114, the diode 115, switch 101, diode 102, and the emitter-collector circuit of transistor 103 to conductor 11, by passing relay 110 and deenergizing that relay with the consequent openingof contact set 111. The next opening of the switch deenergizes winding nzffiiih contact sets 108 and -113 and restoring the circuit to the condition shown in FIG. 7.

Pro. a

At this stage in the discussion it will probably'be recognized that the above described devices can be combined and enlarged to form counters having various capacities. Clearly, it would be redundant and wasteful to attempt to disclose or explain all such permutations and combinations herein, but it should be apparent from the foregoing how such combinations can be made.

In order that the technique can be more clearly understood, one further circuit showing a six-relay counter will be described-with reference-to FIG. 8. In that figure there are six relay windings, 130, 131, 132, 133, 134, and 135. Windings and .131 are connected in series circuit relationship with a normally open contact set 136 which is operated by energization of winding 130. Windings.132 and 133 are connected in series circuit relationship between conductors 10 and 11 with .a normally open contact set indicated generally at 137, this contact set being operated by energization of winding 133. Winding 134 is connected in series circuit relationship with a normally open contact set indicated generally at 138 and a conventional semi-conductor diode 139 between conductors 10 and 11. Winding is connected in series circuit relationship with a normally open contact set indicated generally at 140, contact set 140 being connected to conductor 10 and operated by energization of winding 135. The circuit including winding 135 and contact set 140 is in parallel circuit relationship with winding 134 and diode 139 and in series with contact set 138. A diode 141 is connected across winding 135 to facilitate the energization thereof.

Winding 131 is connected to actuate two single-pole double-throw contact sets indicated generally at 142 and 143, the movable contacts of those contact sets being connected to opposite sides of the push-button switch 151, the openings and 131 closings of which are to be counted. The normally open fixed contact of contact set 142 is connected to conductor 10 and the normally closed fixed contact of contact set 143 is connected to conductor 11. The normally closed fixed contact of set 142 and the normally open fixed contact of set 143 are connected to the movable contacts of contact sets indicated generally at 146 and 147, respectively, which are actuated by energization of winding 132. The normally closed contact of set 146 is connected to the cathode of diode 144 and the normally open contact of that set is connected to the cathodes of diodes 148 and 149. The normally open contact of set 147 is at the junctions with relay windings 132 and 133,

respectively. The anode of diode 149'is connected to the junction between winding 134 and diode 139 and the cathode of diode 156 c o nnected to the junction I between contact set 140 and winding 135.

The operation of this circuit, although it is believed contact sets 142 and 143 to the positions opposite those shown in FIG. 8. The next closure of switch 151 completes a circuit through contact set 142, switch 151, contact sets 143 and 147, diode 152 and winding 133, energizing that winding and closing contact set 137. The next opening of switch 151 energizes winding 132 and causes contact sets 146 and 147 to move to theiropposite positions.

The third closure of switch 151 completes a circuit through contact set 142, switch 151, contact sets 143 and 147, diode 145 and winding 131, deenergizing winding 130 and permitting contact set 136 to open. The next, opening of switch 151 permits winding 131 to deenergize, allowing contact sets 142 and 143 to return to the positions shown in FIG. 8. The fourth closure of switch 151 completes parallel circuits through windings 132 and 13.4 and diodes 148 and 149 to contact set 146, these parallel circuits joining at that point and being in series with the circuit including contact set 142, switch 151 and contact set 143 to conductor 11. This accomplishes, first, the shunting of winding 133, permitting contact set 137 to open, and the simultaneous energization of winding 134 with the closure of contact set 138. The next opening of switch 151 breaks the holding circuit for winding 132 and permits that winding to deenergize, moving contact sets Mind 147 to their positions shown in FIG. 8.

The fifth closure of switch 151'again completes a circuit through winding 130, as in the first closure, permitting that winding to energize and closing contact set 136. At this point, windings 130 and 134 are both energized. The next opening permits winding 131 to energize, switching contact sets 142 and 143. The sixth closure completes a circuit through contact set 142, switch 15], contact set143, contact set 147, diode 152 and winding 133, closing contact set 137. The next opening energizes winding 132 and switches contact sets 146 and 147. At this stage, windings 130, 131, 132, 133 and 134 are all energized. The seventh closure completes a circuit through contact set 142, switch 151, contact sets 143. and 147, diode 150, winding 135 and contact set 138, energizing winding 135 and closing contact set 140 which holds the winding 135 energized. Simultaneously, a parallel circuit exists from contact set 147 through diode 145 and winding 131, shunting winding 130 and permitting its deenergization with the consequent opening of contact set 136. g

The next opening of the switch deenergizes winding 131, leaving windings 132, 133, 134 and 135 energized. The next closing of the switch shunts winding 133, allowing it to deenergize, and the following opening permits winding 132 to deenergize, leaving only windings 134 and 13S energized. The next closing again completes a circuit through windings 130, as in the first closing, and the next opening energizes winding 131. The next closing energizes winding 132. Neither of these afiects the remaining windings, so that at this stage all windings are energized.

From this stage, either of two alternatives can be chosen; one being the actuation of a reset switch, not shown, which would interrupt the supply and deenergize all relays. Alternatively, the switch can be actuated sequentially to deenergize the relays in the kind of pattern previously discussed. A table showing the sequence of events in the circuit of FIG. 8, up to and including full energization, follows.

- TABLE3 WINDING EVENT- I31 132 133134 It will be observed that in several circumstances in the various circuits discussed herein the relays are required to energize under different circumstances, i.e., with one relay connected between the supply conductors or with two relays in series. Accordingly, it will be recognized that the relays must be capable of energizing at a voltage which is less than half of the supply voltage and the windings should also be able to withstand voltages of the magnitude of the supply of voltage, or greater, continuously, without damage. These are not severe restrictions, as will be recognized by those skilled in the art, and can easily be satisfied by reed type relays of the type having a glass enclosure with a surrounding energizing winding and magnetically actuated contacts therein.

It will also be recognized that multiple contact relays of this type can be used, where desired, to provide an output indicating energization states.

While certain advantageous embodiments have been chosen to illustrate the invention, it will be understood by those skilled in the art that various changes and modifications can be made therein without departing from the scope of the invention as defined in the appended claims.

What is claimed is:

1. A counting circuit comprising the combination of a power supply;

a first electrical conductive path connected across said supply, said path including, in series circuit relationship, first and second electromagnetic operators, and a first switch, said first switch being controlled by energization of the first of said operators;

cuit relationship with said first operator and said first switch; 5

a third conductive path connectable in parallel circuit relationship with said second operator and said first switch;

said second and third paths having a common portion;

a second switch in said common portion operable in response to events to be counted;

and third switch means operative in response to energization of said second operator to connect one of said second and a third conductive paths in parallel circuit relationship with the appropriate portion of said first path. a 2. A counting circuit according to claim 1 wherein said first switch constitutes a normally open contact set connected between said first and second operators. 3. A counting circuit according to claim 2 wherein said third switch means includes first and second single-pole double-throw contact sets, the movable contact of each of said contact sets being connected to said second switch, one fixed contact of each of said contact sets being connected to a different terminal of said power pp y, the other fixed contacts of said contact sets being connected to said first switch.

4. A counting circuit according to claim 1 and further comprising a fourth electrically conductive path connected across said supply, saidpath including, in series circuit relationship,

- l6 a third and fourth electromagnetic operators, and

a'fourth switch,

1 said fourth switch being controlled by energization of the third of said operators; and fifth switch means operative in response to the energization state of said fourth operator to selectively interconnect one of said second and third conductive paths with at least a portion of said fourth conductive path. 5. A counting circuitv comprising the combination of a power supply;

a first electrically conductive path connected across I said supply, said path including, in series circuit relationship, first and second operators, and

a first switch, said first switch being controlled by energization of the first of said operators; a second conductive path connectable in parallel circuit relationship with said first operator and said first switch; a third conductive path connectable in parallel circuit relationship with said second operator and said first switch; said second and third paths having a common portion; a second switch in said common portion operable in response to events to be counted; and third switch means operative in response to energization of said second operator to connect one of said first path. 

1. A counting circuit comprising the combination of a power supply; a first electrical conductive path connected across said supply, said path including, in series circuit relationship, first and second electromagnetic operators, and a first switch, said first switch being controlled by energization of the first of said operators; a second conductive path connectable in parallel circuit relationship with said first operator and said first switch; a third conductive path connectable in parallel circuit relationship with said second operator and said first switch; said second and third paths having a common portion; a second switch in said common portion operable in response to events to be counted; and third switch means operative in response to energization of said second operator to connect one of said second and a third conductive paths in parallel circuit relationship with the appropriate portion of said first path.
 2. A counting circuit according to claim 1 wherein said first switch constitutes a normally open contact set connected between said first and second operators.
 3. A counting circuit according to claim 2 wherein said third switch means includes first and second single-pole double-throw contact sets, the movable contact of each of said contact sets being connected to said second switch, one fixed contact of each of said contact sets being connected to a different terminal of said power supply, the other fixed contacts of said contact sets being connected to said first switch.
 4. A counting circuit according to claim 1 and further comprising a fourth electrically conductive path connected across said supply, said path including, in series circuit relationship, third and fourth electromagnetic operators, and a fourth switch, said fourth switch being controlled by energization of the third of said operators; and fifth switch means operative in response to the energization state of said fourth operator to selectively interconnect one of said second and third conductive paths with at least a portion of said fourth conductive path.
 5. A counting circuit comprising the combination of a power supply; a first electrically conductive path connected across said supply, said path including, in series circuit relationship, first and second operators, and a first switch, said first switch being controlled by energization of the first of said operators; a second conductive path connectable in parallel circuit relationship with said first operator and said first switch; a third conductive path connectable in parallel circuit relationship with said second operator and said first switch; said second and third paths having a common portion; a second switch in said common portion operable in response to events to be counted; and third switch means operative in response to energization of said second operator to connect one of said second and third conductive paths in parallel circuit relationship with the appropriate portion of said first path. 